Sealed joint for sectionalized flooring and method of making the same

ABSTRACT

A method of sealing a joint between adjacent structural elements of a sectionalized floor to provide a seal having improved penetration resistance. The seal is formed of a sealant based on a cured liquid polymer, preferably a liquid polysulfide polymer and has a layer of glass cloth embedded therein parallel to and somewhat below the upper surface of the seal. Both the method and the sealed joint are claimed.

United States Patent 1191 Walters Y 1111 3,827,204 1 Aug. 6, 1974 SEALED JOINT FOR SECTIONALIZED FLOORING AND METHOD OF MAKING THE SAME [75] Inventor: Fred L. Walters, Levittown, Pa.

[73] Assignee: Thiokol Chemical Corporation,

Bristol, Pa.

22 Filed: Mar. 14,1972 211 App]. No.: 234,537

[52] US. Cl 52/396, 52/404, 52/573, 404/66 [51] Int. Cl E04f 15/14 [58] Field of Search 52/396, 404, 415, 417, 52/393, 573, 309, 515, 442, 744; 94/17, 18,

[56] References Cited UNITED STATES PATENTS 1,818,704 8/1931 Frantz 52/417 2,064,785 12/1936 Crandell 52/417 2,210,138 8/1940 Bishop 94/18 2,220,444 1 1/1940 Gisslander 94/18.2

2,672,106 3/1954 Lenke 52/442 3,119,204 H1964 Williams 52/396 3,124,047 3/1904 Grahm 52/396 3,145,502 8/1964 Rubenstein 52/515 3,334,558 8/1967 Atkinson... 52/396 3,478,480 1 H1969 Swenson 52/396 3,491,499 1/1970 Dyer 52/396 FOREIGN PATENTS OR APPLICATIONS 1,275,460 10/1961 France 52/417 188,741 2/1957 Austria 94/17 Primary Examiner-Frank L. Abbott Assistant ExaminerH. E. Raduazo [5 7] ABSTRACT A method of sealing a joint between adjacent structural elements of a sectionalized floor to provide a seal having improved penetration resistance. The seal is formed of a sealant based on a cured liquid polymer, preferably a liquid polysulfide polymer and has a layer of glass cloth embedded therein parallel to and somewhat below the upper surface of the seal. Both the method and the sealed joint are claimed.

1 Claim, 2 Drawing Figures SEALED JOINT FOR SECTIONALIZED FLOORING AND METHOD OF MAKING THE SAME This invention relates to sectionalized flooring constructed of structural elements which are blocks or slabs of materials such as concrete, stone, ceramic or terrazzo tiles, slate and the like with the adjacent edges of the structural elements defining joints that are filled with an elastic seal. More particularly, the invention relates to a novel and improved method of making the elastic seal in such joints, as well as to the resulting sealed joints.

Sectionalized flooring of the type referred to above is extensively used in both indoor and outdoor applications for patios, malls, plazas, the floors of public buildings and the like which are subjected to extensive pedestrian traffic. As indicated above, the joints between adjacent structural elements of the floor are commonly filled with elastic seals to accomodate thermal expansion and contraction which would otherwise cause cracking, flaking or other disintegration of the surface of the floor. Numerous materials have been proposed for sealing the joints between the structural elements of such flooring. However, especially good results have been obtained by sealing such joints with sealant compositions based on liquid polymers that are readily curable to elastomeric form, especially polysulfide polymer-based sealants.

Polysulfide polymer-based sealants are well known in the art and have been extensively used for forming elastomeric seals between surfaces of such materials as metals, glass, concrete and the like. When properly formulated and cured, they form elastomeric seals that are highly resistant to moisture, sunlight, temperature variations and solvents and retain their elastomeric character after exposure to varying atmospheric conditions for long periods of time.

The polysulfide polymers commonly used in polysulfide based sealants are liquid polymers that may be prepared, for example, as described in US. Pat. No. 2,466,963. As disclosed in the latter patent, high molecular weight polymers can be prepared which can then be split to form polythiopolymercaptan polymers having molecular weights of the order of 300 to 25,000 and which are viscous liquids having viscosities within the range 300 to 150,000 centipoises at 25C. Such liquid polymers can be cured by any of various curing agents as disclosed in U.S. Pat. No. 2,466,963 to form solid elastomers having excellent resistance to acids, alkalis, petroleum hydrocarbons and atmospheric moisture and oxidation. In general, such polymers may be represented by the formula HS(RS n)m SH wherein n has an average value of 1.5 to 5, m may vary from say 2 to 70 and R is a divalent hydrocarbon, oxahydrocarbon or thiahydrocarbon radical. One of the most widely used types of liquid polythiopolymercaptan polymer is made by reacting bis-beta-chloroethylformal with a sodium sulfide solution in the presence of a small percentage of trichloropropane to form a solid polymer which when split as disclosed in US. Pat. No. 2,466,963 yields a liquid polymer largely composed of the recurring units (SCH CH OCH OCH CH S) and having free mercapto terminals and from say 0.1 to 4 percent of cross-linking.

As disclosed in US. Pat. No. 2,466,963, the liquid polymers can be cured by a wide variety of curing agents to form solid elastomers having excellent resis tance to acids, alkalis, petroleum hydrocarbons and atmospheric oxidation. Suitable curing agents include organic oxidizing agents such as benzoyl peroxide, dicumyl peroxide, dibutyl tin oxide and nitrobenzenes; and inorganic peroxides including the alkali metal and alkaline earth metal peroxides, such as sodium peroxide, lithium peroxide, calcium peroxide, barium peroxide; as well as zinc peroxide, lead peroxide, antimony peroxide, manganese dioxide and sodium perbonate.

Sealant compositions based on the liquid polysulfide polymers commonly contain in addition to the polymer and curing agent various additives such as finely divided inorganic fillers, plasticizers, thixotropic agents, cure accelerating or retarding agents and adhesion promoters. The sealant may be of the twopart or one-part type. In the case of two-part sealants, the liquid polymer and one or more additives may be placed in one package and the curing agent and one or more additives in a second package. The two packages are shipped to the point of use and mixed just prior to being used. Such two-part sealants are disclosed, for example, in US. Pat. Nos. 3,349,047; 3,312,669 and 3,328,451.

One-part or one-package sealants based on liquid polythiopolymercaptan polymers are disclosed, for example, in US. Pat. Nos. 3,225,017; 3,349,047 and 3,499,864. In general, such one-part sealants are formulated by using curing agents which do not react with the liquid polymer at ambient temperature when kept in a sealed package but when exposed to the atmosphere become activated by atmospheric moisture or oxygen to effect the desured cure of the polysulfide polymer. In certain of the one-part sealant compositions as disclosed, for example, in US. Pat. No. 3,225,017, a deliquescent accelerating agent is included in the composition to accelerate the cure when the sealant composition is exposed to the atmosphere. Such accelerating agents may include alkali metal and alkaline earth metal oxides, peroxides and hydroxides.

While polysulfide-based sealants of the type described above have been extensively used to seal the joints in sectionalized flooring and have many advantageous properties when so used, it has been found that especially in applications where the flooring is subjected to heavy pedestrian traffic, the resistance of the cured sealant to localized deformation is not as great as is desirable. More particularly, it has been found that ladies high heeled shoes, especially the so-called spike heels, tend to penetrate the cured sealant. When such penetration of the sealant occurs, the heel of the shoe may become entrapped, thus causing the wearer of the shoe to fall or sustain a wrenched or sprained ankle. Thus such sealed joints as previously formed and used present a significant hazard to pedestrian traffic. Also the cavities formed in the sealant produce an unsightly appearance.

It is accordingly an object of the present invention to provide a method of sealing the joints in sectionalized flooring in such manner as to provide an elastomeric seal having increased penetration resistance, and especially resistance to penetration by ladies high heels. It is another object of the invention to provide a sealed joint in a sectionalized floor, which joint sustains no permanent deformation when subjected to the pressure of a spike heel worn by a woman walking thereon. It is still another object of the invention to protect pedestrians wearing high-heeled shoes from the hazards arising out of penetration of the joint sealant material by such high heels. It is a still further object of the invention to eliminate the unsightly appearance of cavities in the exposed surface of the joint sealant produced by sharpheeled shoes. Other objects of the invention will be in part obvious and in part pointed out hereafter.

The objects of the invention are achieved in general by providing a sealed joint in which the sealant material has a horizontal, reticulate reinforcing layer embedded therein just below the upper surface of the sealant. It has been found that when the proper type of reinforcing layer is properly positioned within the sealant of the joint, the penetration resistance of the seal is greatly enhanced. More particularly, it has been found that when a glass cloth reinforcing layer is embedded in the sealant slightly below its upper surface, the tendency of high heels of ladies shoes to form cavities in the surface of the sealant is eliminated. For example, in a test installation made in the manner described hereafter, a spiked heel worn by a 140-pound woman standing on the joint produced no detectable deformation of the upper surface of the seal.

As pointed out below, the reinforcing strip desirably has a width substantially equal to the width of the joint, but it need not be attached or secured to the adjacent walls of the sections to be sealed. It has been found surprisingly that by merely embedding a strip of glass cloth slightly below the upper surface of the sealant without anchoring it to the side walls of the joint an unexpectedly large increase in the penetration resistance of the surface of the sealant is achieved. Also it has been found that incorporation of the glass cloth layer in the sealant does not adversely affect the physical properties of the resulting joint.

The objects and advantages of the invention may best be understood and appreciated by reference to the accompanying drawing which illustrates a sealed joint incorporating a preferred embodiment of the invention and wherein:

FIG. I is a vertical section on a greatly enlarged scale through a portion of a concrete block floor showing a pair of blocks and the sealed joint therebetween; and,

FIG. 2 is a vertical section taken on the line 2--2 of FIG. 1 and further showing the relationship between the components of the seal.

Referring to the drawings and particularly to FIG. 1, the numerals l and 12 designate a pair of concrete blocks having the confronting spaced vertical surfaces 14 and 16 which define a joint generally designated 18. In forming a seal within joint 18 according to a preferred embodiment of the method of the invention, a resilient rope 20 having an unstressed diameter somewhat larger than the width of the joint is forced or wedged into the joint to form a support for the subsequently introduced components of the seal. The rope 20 may be made, for example, of a foamed plastic, e.g., polystyrene, polyethylene, polypropylene or polyurethane. While the rope as shown in the drawing has a circular cross-section in its unstressed condition, it will be evident that the rope may have any other crosssectional configuration that will permit to perform its function of a back-up material for the sealant. For example, the rope may be of oval or polygonal crosssection.

After the rope 20 is in place, a quantity of a liquid curable polysulfide sealant is poured into the joint to form a lower sealant layer 22. As pointed out below, the sealant composition desirably has an adhesion pro moter incorporated therein to cause the cured sealant to adhere firmly to the walls 14 and 16 of blocks 10 and 12. Also, if desired, conventional primer solutions can be applied to the walls 14 and 16 before the seal is formed in the joint to promote adhesion of the sealant to the walls.

A glass cloth tape 24 preferably having a width approximately the same as the width of the joint, is then placed on top of the lower sealant layer 22 and pressed slightly downward to cause the viscous sealant composition to flow into the interstices of the glass cloth. Thereafter additional sealant 26 is poured into the joint to a level just below, say one-eighth inch below, the upper surface of blocks 10 and 12, and the sealant layers are permitted to cure to elastomeric form. The reason for filling the joint to a level slightly below the upper surfaces of blocks 10 and 12 is to ensure that upon thennal expansion of the blocks the sealant will not bulge upwardly above the surfaces of the blocks. In the drawing the upper surface of the cured sealant is shown as planar. However, it will be understood that at relatively low ambient temperatures thermal contraction of the adjacent blocks may cause the upper surface of the sealant to become concave, whereas at exceptionally high ambient temperature the upper surface of the sealant may bulge upwardly to give the sealant surface a convex configuration. As shown in the drawing, in the cured seal the glass cloth is embedded in the cured sealant material parallel to and slightly below the upper surface of the sealant and thus reinforces the sealant surface against penetrative deformation.

It is evident that the dimensions of the joint and the components of the seal will vary as a function of the nature and size of the structural elements used in constructing the sectionalized flooring. In typical applications using relatively large cement blocks the dimensions of the seal may fall within the following ranges:

Width ofjoint 18 V4" to l" Unstressed diameter of rope 20 W to 1%" Vertical distance between top of blocks and upper surface of sealant Vs" to V4" Vertical distance between upper surface of sealant and top of rope 20 '15" to I" Vertical distance between upper surface of sealant and center of glass cloth 24 PartA Component Parts by Weight PbO (curing agent) Butyl benzyl phthalate (Santicizer 160 plasticizer) 52 Bisphenol A-epichlorohydrin epoxide (Tipox B adhesion promoter) 4 Part A and Part B are separately formulated and thoroughly mixed just prior to use.

As pointed out above, it has been found that by forming a seal in the manner described above with a layer of glass cloth embedded in the sealant material just below the upper surface of the sealant, the resistance of the upper surface of the sealant to penetrative deformation is greatly enhanced. Moreover, tests of such seals have shown that the use of the glasscloth in the seal did not diminish the effectiveness of the seal as an expansion joint.

It is, of course, to be understood that the foregoing description is intended to be illustrative only and that numerous changes can be made in the materials and procedure described without departing from the scope of the invention as defined in the appended claims. Thus other conventional sealant compositions may be substituted for the polysulfide base sealant referred to above. For example, sealant compositions based on liquid polyurethane prepolymers of the polyester or polyether type may be used. As is known in the art, such liquid urethane prepolymers have isocyanate terminals and may be cured with, for example, polyepoxides and polyamines. Also sealant compositions based on silicone polymers, for example, silicone polymers of the type disclosed in US. Pat. No. 3,189,576, which silicone polymers are air-curable may be used. Other modifications of the invention will be apparent to those skilled in the art.

I claim:

1. As an article of manufacture, a pair of spaced structural elements selected from masonry blocks, ceramic tiles and slate, said elements forming part of a floor essentially composed therof and defining a joint therebetween, a rope of resilient supporting material wedged in said joint to a point spaced below the upper surfaces of said elements, a body of cured polysulfide base sealant substantially filling the space in said joint above said resilient rope and adhered to the sides of said joint, and a horizontal layer of glass cloth tape having a width substantially equal to the width of said joint embedded in said body of cured sealant slightly below the upper surface thereof.

I UNITED STATES PATEN'L OFFI (I F. CRTIFICATE UP CORRECTION Patent No. 3 827 ,204 Dated August 6 1974 Inventofls) Fred 1.5; Walte gs It is certified that error appears in the aboveddentified patent and that said Letters Patent are hereby corrected as shown below:

Change the name of the Assignee from "Thiokol Chemical Corporation" to "Thiokol Corporation" Signed and sealed this 5th day of November 1974.

(SEAL) Atte$tz MCCOY Mo GIBSON JR. C. MARSHALL'DANN tteetin Officer Commissioner of Patents 

